test heap reclaim

mem.js

function foo() {
  var a  = [];
  for (var i = 0; i < 20000000; i++) {
    a.push({});
  }
}

function repeat() {
  printMem('before alloc');
  foo();
  printMem('before gc');
  gc();
  printMem('after gc');
}

function printMem(label) {
  var mem = process.memoryUsage();
  for (var p in mem) {
    // convert to MB
    mem[p] = mem[p] / 1000000;
  }
  console.log(label, mem);
}

setInterval(function() {
	repeat();
}, 1000);

/** SAMPLE RUN
before alloc { rss: 18.518016, heapTotal: 9.751808, heapUsed: 3.452184 }
before gc { rss: 828.45696, heapTotal: 806.798592, heapUsed: 783.449728 }
after gc { rss: 60.657664, heapTotal: 46.335488, heapUsed: 3.395112 }
before alloc { rss: 60.657664, heapTotal: 46.335488, heapUsed: 3.450048 }
before gc { rss: 830.34112, heapTotal: 808.895232, heapUsed: 782.113792 }
after gc { rss: 62.316544, heapTotal: 48.39936, heapUsed: 3.40172 }
before alloc { rss: 62.316544, heapTotal: 48.39936, heapUsed: 3.453744 }
before gc { rss: 830.283776, heapTotal: 808.895232, heapUsed: 782.11828 }
after gc { rss: 62.93504, heapTotal: 48.39936, heapUsed: 3.403368 }
before alloc { rss: 62.93504, heapTotal: 48.39936, heapUsed: 3.453104 }
before gc { rss: 830.283776, heapTotal: 808.895232, heapUsed: 782.11828 }
after gc { rss: 61.886464, heapTotal: 47.367424, heapUsed: 3.403368 }
before alloc { rss: 61.886464, heapTotal: 47.367424, heapUsed: 3.453128 }
before gc { rss: 830.283776, heapTotal: 808.895232, heapUsed: 782.11828 }
after gc { rss: 62.93504, heapTotal: 48.39936, heapUsed: 3.403368 }
before alloc { rss: 62.93504, heapTotal: 48.39936, heapUsed: 3.453104 }
before gc { rss: 830.283776, heapTotal: 808.895232, heapUsed: 782.11828 }
after gc { rss: 61.886464, heapTotal: 47.367424, heapUsed: 3.403368 }
*/